Integrated Circuit with a Laterally Diffused Metal Oxide Semiconductor Device and Method of Forming the Same

Abstract

An integrated circuit with a transistor advantageously embodied in a laterally diffused metal oxide semiconductor device having a gate located over a channel region recessed into a semiconductor substrate and a method of forming the same. In one embodiment, the transistor includes a source / drain including a lightly or heavily doped region adjacent the channel region, and an oppositely doped well extending under the channel region and a portion of the lightly or heavily doped region of the source / drain. The transistor also includes a channel extension, within the oppositely doped well, under the channel region and extending under a portion of the lightly or heavily doped region of the source / drain.

Description

[0001]This application is a continuation in part of, and claims priority to, U.S. patent application Ser. No. 11 / 805,233, entitled “Laterally Diffused Metal Oxide Semiconductor Device and Method of Forming the Same,” filed on May 22, 2007, which is a divisional of U.S. patent application Ser. No. 10 / 767,684, entitled “Laterally Diffused Metal Oxide Semiconductor Device and Method of Forming the Same,” filed on Jan. 29, 2004, now, U.S. Pat. No. 7,230,302, issued Jun. 12, 2007, all of which are incorporated herein by reference.TECHNICAL FIELD[0002]The present invention is directed, in general, to integrated circuits and, more specifically, to an integrated circuit with a laterally diffused metal oxide semiconductor device and method of forming the same.BACKGROUND[0003]The design of early integrated circuits focused on implementing an increasing number of small semiconductor devices on a semiconductor substrate to achieve substantial improvements in manufacturing efficiency and cost, p...

AI Technical Summary

Benefits of technology

[0016]These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by advantageous embodiments of the present invention, which includes an integrated circuit formed on a semiconductor substrate and configured to accommodate higher voltage devices and low voltage devices therein. In one embodiment, the integrated circuit includes a transistor advantageously embodied in a laterally diffused metal oxide semiconductor (“LDMOS”) device having a gate located over a channel region recessed into a semiconductor substrate. The transistor also includes a source/drain including a lightly or heavily doped region adjacent the channel region, and an oppositely doped well extending under the channel region a...

Problems solved by technology

An objective of incorporating control and signal processing devices on a semiconductor substrate with the higher voltage devices often encounters conflicting design requirements.

Since the cost of an integrated circuit is roughly proportional to the number of processing steps to construct the same, there has been limited progress in the introduction of low cost integrated circuits that include both control and signal processing devices and higher voltage devices such as the switches of the power train of a power converter.

Inasmuch as the cost of a die that incorporates the integrated circuit is roughly proportional to the area thereof, the presence of the higher voltage devices conflicts with the reduction in area achieved by incorporating the fine line features in the control and signal processing devices.

While a design and implementation of low voltage devices such as logic devices that form portions of a microprocessor have been readily incorporated into integrated circuits, the systems that power the logic devices have not to date been readily incorporated into integrated circuits.

Although power converters have shown dramatic improvements in size, cost, and efficiency over the past few decades, the design of the power converters have not kept pace with the improvements in integrated circuit technology directed to the logic devices and the like, which follow Moore's Law demonstrating a doubling of device (e.g., transistor) density about every 18 months.

While Balakrishnan and other references have demonstrated noticeable improvements of incorporating power converters into an integrated circuit, an industry wide integration of higher voltage level devices (again, such as the switches of the power train) into the design of integrated circuits, especially in power converters, has not yet gained industry wide adoption.

Another issue in a design of the power converters is an increase of the switching frequency (e.g., five megahertz) of the power train thereof.

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